<!DOCTYPE html>
<html>
<head lang="en">
	<meta charset="UTF-8">
	<title>Prototype Extention</title>

	<script src="prototype.js"></script>
</head>
<body>

<script>
	var arr = ['a', 'a', 'b', 'a', 'c', 'd'];
	console.log(arr.unique());//["a", "b", "c", "d", unique: function]
</script>
</body>
</html>